Could I be pregnant?

Had sex the end of July when I was on ovulation 4 days later(very begin of august) I got my period( 2 days and light not my normal period ! ) Ik for the egg to attach it takes 6-12 days! Since Sunday I've had cramps in my lower stomach/ felt nauseous/ headaches/ tired / sore boobs

My period isn't due till next Thursday and ive felt like this for 6 days and my period is 7 days away still!

Any idea?!